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Offset quadrature phase-shift-keying method and optical transmitter using the same

A phase-shift keying and optical transmitter technology, applied in electromagnetic transmitters, applications, optics, etc., can solve problems such as performance limitations of optical communication systems, QPSK signal beam deterioration, etc.

Inactive Publication Date: 2006-07-26
SAMSUNG ELECTRONICS CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, as is well known in optical communication systems, narrow-band optical filters tend to deteriorate the QPSK signal beam because the QPSK signal beam has a phase transition of 180°
Because the optical transport network includes many optical filters, the performance of the optical communication system using the QPSK scheme is limited

Method used

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  • Offset quadrature phase-shift-keying method and optical transmitter using the same
  • Offset quadrature phase-shift-keying method and optical transmitter using the same
  • Offset quadrature phase-shift-keying method and optical transmitter using the same

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Embodiment Construction

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals designate the same or similar elements even if they are in different drawings. For the purpose of clarity and conciseness, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

[0022] figure 1 is a block diagram of an optical transmitter 100 using an offset quadrature phase shift keying (OQPSK) modulation method according to the first embodiment of the present invention. figure 2 By figure 1 A timing diagram of signal beams processed by the optical transmitter 100 is shown. As shown, the optical transmitter 100 includes a light source (LS) 110 and an OQPSK modulator (OQPSKM) 120 . OQPSKM 120 includes first and second optocouplers (OC) 130 and 180, first and second phase modulators (PM) 140 and 150, phase delay unit D P 170, and bit delay unit D ...

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Abstract

Disclosed is an optical transmitter using an offset quadrature phase-shift-keying (OQPSK) method. The method includes: a first phase modulator for outputting a first signal beam generated by phase-modulating an input beam based on a first data; a second phase modulator for outputting a second signal beam generated by phase-modulating the input beam based on a second data; a phase delay unit for granting a predetermined phase difference between the first signal beam and the second signal beam; and an optical coupler for coupling the first signal beam and the second signal beam between which the phase difference exists.

Description

technical field [0001] The present invention relates generally to an optical transmitter used in an optical communication system, and more particularly, to an optical transmitter using an Offset Quadrature Phase Shift Keying (OQPSK) method. Background technique [0002] Due to the growing demand for faster data rates through backbone networks, efforts are being made to increase the transmission capacity of a single optical fiber. One way to improve the transmission capacity of an optical communication system is to use a wavelength division multiplexing (WDM) scheme to increase the number of channels in the system. Another approach is to increase frequency utilization, which uses a narrow channel bandwidth modulation scheme. In this method, more channels can be carried on a given bandwidth by narrowing the channel spacing. However, with binary signals, no more than 1 bit of data can be carried on a unit frequency. This is supported by Shannon's theory. Therefore, in order...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/145H04L27/20H04B10/40G02F1/03H04B10/50H04B10/516H04B10/548H04B10/588H04B10/60H04B10/61
CPCH04B10/505H04B10/5561H04B10/5053H04B10/5051A45D33/36A45D34/04A45D40/26A45D2033/001A45D2034/002A45D2040/0006A45D2200/1009Y10S206/823
Inventor 金薰黄星泽
Owner SAMSUNG ELECTRONICS CO LTD